Question

an exponential function is written as $f(x) = a \cdot b^x$, where the coefficient $a$ is ______, the base $b$ is positive but not equal to 1, and the exponent $x$ is any number.\
\
\\(\bigcirc\\) a. a variable\
\\(\bigcirc\\) b. an integer\
\\(\bigcirc\\) c. an exponent\
\\(\bigcirc\\) d. a constant

Explanation:

In the exponential function \( F(x)=a\cdot b^{x} \), the coefficient \( a \) is a constant. A variable (option A) would change, but \( a \) is fixed for a given exponential function. An integer (option B) is too restrictive as \( a \) can be a non - integer real number. The exponent is \( x \), so \( a \) is not an exponent (option C). So \( a \) must be a constant.

Answer:

D. a constant